Gerald takes the bracelets back. Nisos starts moving the statue's arms around. There must be an advanced mechanism hidden inside them; it seems they can be moved into any position real arms could be moved to. There is nothing of note in the armpits. Nisos pulls at an arm, but it doesn't detach.

Remus: Harry... I'm a werewolf.
Harry: Are you fucking serious?
Remus: Well yes, but I don't see how that applies here.

Gerald puts the goblin bracelet into the door hole. The pins grip it and retract, but nothing happens. He puts the elf bracelet into the hole instead. The pins grip it tightly, fitting into the bracelet's pattern, and then retract. A click is heard, and the door swings open outwards, revealing a small chamber. A stone piedestal stands in the middle of the chamber, and on top of that is a metal scroll case, identical to the one you found before which Saucix now carries. But this one has its lids on at both ends.